PAC study on the thermal evolution of the 60ZrF₄–40BaF₂ glass

Abstract

By using ¹⁸¹Ta probes, the PAC technique has been used to investigates the behaviour of the hyperfine interaction in 60ZrF₄–40BaF₂ glass from room temperature (RT) up to the glass temperature T_g (562 K). A first serie of measurements was obtained while heating the as-prepared sample from RT to T_g. A second serie was performed on the as-treated sample after cooling it down to RT and again heated to T_g. In both series the same three components of the quadrupole interaction were observed. Dynamical effects were detected in the main component and activation energies of 0.18₁ eV and 0.21₃ eV were obtained. The results are interpreted as dynamical effects associated to the movement in the fluorine ions during polyhedra rearrangements.